ann11076 — Announcement

ESOcast 38: Faraway Eris is Pluto's Twin

Astronomers have accurately measured the diameter of the faraway dwarf planet Eris for the first time by catching it as it passed in front of a faint star. This event was seen at the end of 2010 by telescopes in Chile, including the Belgian TRAPPIST telescope at ESO’s La Silla Observatory.

The observations show that Eris is an almost perfect twin of Pluto in size. Eris appears to have a very reflective surface, suggesting that it is uniformly covered in a thin layer of ice, probably a frozen atmosphere.

This ESOcast takes a look at the clever technique that the astronomers used and what they have found out about Eris.